I got a ATEM Television Studio and in it´s Tech Specs. for the format 4:3 it´s 625/25. I would like to use a camera (JVC GY-HD750) that has the ability to provide 576/50i. Will I be able to connect the camera to TV Studio in 4:3 PAL format?

I tried to google it and as far as I understand, the 576 and 625 is the same? 720x576 is what we see, and the rest of the signal up to 720x625 is for other information?

You'll be fine - 625 is the analogue version of 576:http://en.wikipedia.org/wiki/576i
"In analogue 49 additional lines without image content are added to the displayed frame of 576 lines to allow time for older CRT circuits to retrace for the next frame"
(http://en.wikipedia.org/wiki/Vertical_blanking_interval)